So I found this for one of my challenges:
http://virtualpiano.net/
Click that and click menu above the keys. Then click key assist and it should look like this
piano.png
Then go to the music sheets section
http://virtualpiano.net/tag/easy/
And they'll show you how to play some song
The letters written under are the keys on your keyboard to press. So Mary Had A Little lamb is
apopaaa
ppp add
apopaaa
appapo
So just type that and you'll play Mary Had A Little Lamb
TA DA
I am having so much fun with this